Electro-cardiographic patient monitoring and morphology recognition method

ABSTRACT

An electro-cardiographic patient monitoring and morphology recognition method utilizing a digital computer which is shared by eight patients. The ECG signal of each patient is sampled at 8-millisecond intervals, with samples of different patients being provided to the computer at 1-millisecond intervals. The computer is programmed to recognize atypical characteristics in the ECG signals and to control a 3-second analog recording of the ECG signal of any patient for whom an atypical condition is determined.

United States Patent I [191 Harris Apr. 30, 1974 ELECTRO-CARDIOGRAPHICPATIENT 3,606,882 9/1971 Abe et a1. 128/206 A M TO G AND MORPHOLOGY3,654,916 4/1972 Nielsen 128/206 A I 3,618,693 11/1971 Nachev et al....128/206 A RECOGNITION METHOD 3,434,151 3/1969 Bader et a1 128/206 R [75]Inventor: George J. Harris, Framingham,

MaSS- Primary ExaminerWilliam E. Kamm [73] Assignee: American OpticalCorporation Attorney, Agent, or FzrmJoel Wall; Wllltam C.

Southbridge, Mass. Neale [22] Filed: Oct. 26, 1971 [57] ABSTRACT [21]APPI- N04 192,191 An electro-cardiographic patient monitoring and mor-Related US. Application Data Continuation-impart of Ser. No. 820,554,April 30,

1969, Pat. No. 3,616,791.

phology recognition method utilizing a digital computer which is sharedby eight patients. The ECG signal of each patient is sampled at8-millisecond intervals, with samples of different patients beingprovided to the computer at l-millisecond intervals. The com- [fi] .1puter is programmed to recognize atypical characteris 5 i R 2 tics inthe ECG signals and to control a 3-second ana- 1 le 52 G 2 l logrecording of the ECG signal of any patient for l whom an atypicalcondition isdetermined.

[56] References Cited 5 C 0 Dr UNITED STATES PATENTS aw'ng gums3,658,055 4 1972 Abe et a1. 128/206 A 3,524,442 8/1970 Horth 128/206 A12? 14 ON *L E NQP EAYll 1 5, T1

12-0 l4- 0 ON ZSECOND DELAY RECORDER F d 1' 1B ANALOG L ANALOG I I6 AID32 E06 E MULTIPLEXER CONVERTER 6 38 SIGNALS 7 DATA LINE 5 26 7 46OMPUTER ADDER INTERBUPT LINE +|1o 1 DA Lni INTERRUPT 30 so LINE 2O\PAHENT KEYBOARD COUNTER ND 4o PRINTER PA'TENTEDAPR 30 1914 SHEET 03 0F'24 STWORD RWORD TTY 3 i ADP A FDP AREA ENLARGED EXECUTIVE Z LFP ARPIARP2 lMINTMR L1 L% l PENLRGD ZSECTMR RRTMR v l 3SECTMR 256MSTMR NDP VTCPI MAX i r V y DFP HFPI TCP2 TYPE LDP F|LTAR Z THRESH V DIFSUM HEPAVI-EV MoRPH RRTMR I DMAX l MTYPE I Y Y MRP LTYPE DTP2 RWD I UNLRNDPUNLRND PENLRGD ENLRGD LEGEND Cp DTHRESH RRNEW STWORD MORPH EVERY R wAvERWORDY l/RP MORPH EVERY DP RRP VPB L l PENLRGD l l ,7

L D MFP FVP LATE PRE EPRE CP EN Re EVERY STROBE v I EvERY 2 SECONDSMULTIFORM FREQUEN W EvERY 25s MILLISECONDS MULTIPLE PATENTEBAPR 30 I974I saw on [F 24 DFP START GET DIFFERENTIAL BUFFER POINTER FOR CURRENTPATIENT GET LDP;

GET NDP NDP LDP DIFF', NDP- LOP GET OLDEST- DIFF VALUE POINTER FROM4"WORD BUFFER USING DIFSUM DIFF DIFSUMI INCREME NT POINTER USE POINTERTO INSERT DIFF IN BUFFER,

005s POINT PAST POINT E OF BUFFER ER ND YES IRESET POINTER TO START OFBUFFER STORE POINTER RETURN PATIENTIEO PATIENT# 7 g1; POINTER 3:5: EDIFF DIFF DIFF DIFF DIFFE RE NTIAL BUFFER DIFFERENTIAL BUFFERPATENTEUAPR 30 I914 3.807; 392

sum "as or 24 was IDIFSUMI+DMAX I RETURN I DTP2 START l [GET DMAX BUFFERPOINTER FOR CURRENT PATIENT GET OLDEST DMAX VALUE FROM 8-WORD BUFFERUSING I [SUBTRACT OLDEST DMAX VALUE FROM DTSUM l \ADD NEW DMAX VALUE ToDTSUM IDTSUM I6 --*MDTH'RESH USE POINTER TO INSERT'NEW DMAX VALUE INBUFFER; INCREMENT POINTER DOES POINTER POINT PAST END OF BUFFER YES'[RESET POINTER To START OF DMAX BUFFER I I STORE POINTER CLEAR DMAXPOINTER IEI] APR 30 1974 P1 8 07 l 392 SHEET :06 0F 24 FIG] ' STRTMR- =0FoR CURRENT CLEAR YTRYNEG INCREMENT TRYNEG CONVERT PATIENT NUMBER TO BITPOSITION AND SET CORRESPONDING YES BIT IN RWORD I [RRTMR-RRNEW,1:FSTRTMRI v V [iLEAR TRYPos'. CLEAR TRYNERT INCREMENT STRTMRSTRTMR I YES V CONVERT PATIENT NUMBER TO snposmou AND SET CORRESPONDINGarrm STWORD 0- STRTMRZ 0* MTYPE'; LOAD MOP POINTER WITH ACHK RETURNPATENTEUAPR30 m4 3.807.392

SHEET 07 0F 24 RRP START IRRNEW- RROLDI R RINT YES |+ LATE IE RE ISECPRE I 0- SECPRE l- PRE [l- EPRE] lo v- EPRE1 PATENTEIIAPR 30 I374SHEET [J8 GET RRINT BUFFER PO NTER FOR cuRRENT PATIENT GET OLDEST RRINTVALUE FRO-M 8-WORD BUFFER USING POINTER I SUBTRACT OLDEST RRINT VALUEFROM INTSUM AND STORE RESULT AS PRTLSUM [ADD NEW RRINT VALUE TO PRTLSUMAND STORE RESULT YES PRTLSUM- INTSUM USE POINTER To INSERT zERo INBUFFER, INCREMENT POINTER I ovE RFLOW IN NEWSUM POINTER POINT PAST ENDOF BUFFER AS NEWSUM NEWSUM INTSUM VALUE IN BUFFE I USE POINTER TO INSERTNEW RRINT R, INCREMENT POIN ER I/8 INTSU YES RESET POINTER TO START OFRRINT BUFFER STORE POINTER I HFPI sTART GL r FILTAR NDP +-F|LTAR FIG. I0

[HF V52 0F FILTAR VALUE FoR CURRENT PATIENT? GET HF BUFFER POINTER FORCURRENT PATIENT IEET OLDEST HF VALUE FROM 8-WORD BUFFER usme PQINTER] ILSUBTRACT OLDEST HF VALUE FROM HFSUM T LADD NEW HF VALUE T0 HFsuMT I USEPOINTER T0 INSERT NEW vALuE IN BUFFER, INCREMENT POINTER 7 V8 uFsum-Avu-zvj I YES RESET POINTER TO START. OF HF auFFERI v STORE POINTERICLEAR FILTAR I LFP START I FIGII GET ADP BUFFER POINTER FOR CURRENTPATIENT [GET OLDEST ADP VALUE FROM 4'- WORD BUFFER USING POINTER ADD NEWADP VALUE TO FILSUM FILSUM '1- 4 FDP USE POINTER TO INSERT NEW ADP VALUEIN B UFFER',

INCREMENT POINTER DOES POINTER POINT PAST END OF BUFFER YES RESETPOINTER TO START OF BUFFER STOR E POINTER RETURN PAT-ENTEOAPR 30 1974SHEET "11 0F 24 DOES I FDP I+ AREA GIVE OVERFLOW ARPI START YES I I AREAFDP|+AREA I RETURN I ARP2 START ENLRGD-Q PENLRGDI AREA . L25 AAV YES [IENLRGIZTI GET AREA BUFFER POINTER FOR CURRENT PATIENT GET OLDEST AREAVALUE FROM 8*WORD BUFFER USING POINTER] SUBTRACT OLDE ST AREA VALU EFROM AREASUM AND STORE RESULT AS PRTLSUM :ATENTED R 30 I914 3.8071392sum 12 0f 2 1 ADD NEW AREA VALUE TO PRTLSUM AND STORE RESULT AS NEWSUMOVERFLOW 7 N0 IN NEWSUM PRTLSUM AREASUM mzwsum AREASUIVI USE POINTER TOINSERT ZERO IN BUFFER; INCREMENT POINTER USE POINTER TO INSERT'NEW AREAVALUE IN BUFFER INCREMENT POINTER DOES POINTER POINT PAST END OF BUFFERYES RESET POINTER TO START OF AREA BUFFER STORE POINTER, CLEAR AREARETURN we AREASUM --AAvI TC Pl START FIG. I

YES

1| POP *MAX RETURN GET MAX BUFFER POINTER FOR CURRENT PATIENT GETOLDEST'MAX VALUE FROM 8-WORD BUFFER USING POINTER [SUBTRACT OLDEST MAX-VALUE FROM TsuMT.

ADD NEW MAX VALUE TO TSUM USE POINTER TO INSERT NEW MAX VALUE IN BUFFER;

INCREMENT POINTER noes POINTER POINT PAST NO END OF BUFFER YES RESETPOINTER TO START- OF MAX BUFFER I STORE POINTER, CLEAR MAX PATENTEUAPR30 I914 3.807.392

sum n or 24 LEGEND MCP START AZFDP +THRESH BIFDP THRESH CIDIFSUM.-THRESH BRANCH T0 MCP v DIDIFSUN| 'l' THRESH POINTER FOR CURRENTPATIENT w 1 v ACHK DCHKI ADCHK CCHK2 CC HK1 CBCHK DCHKZ RETURN YES IMTYPE RETURN (OOOOOOOI) (TYPE 1) 8" "TYPE v tqooloooo) v (TYPE 5) ccmq.No

ECHKI-HACP- POINTER] YES ocmu:

SHIFT MTYPE RETURN (oooooow) Q .(TYPE 2) @cmu -MCP QINTEFI YES SHIFTMTYPE RETURN (OOIOOOOO) (TYPE 6) PATENTEDAPR so I974 3 sum 15 or 24CBCHKI ADCHKI ICBCHK MCP POINTER] YES LAocHK+McP POINTER] FIGEGB YEs-SHIFT MTYPE RETURN SHIFT MTYPE (OOOOOIOO) (0:000000) (TYPE 3) (TYPE 7CCHKZZ DCHKZI YES DCHK2 MCP POINTER] RETURN] YES' SHIFT MTYPE C SHIFTMTYPE 7 00000000) I (00001000) (TYPE 8 (TYP 4 SET MCP POINTER TO RETURNRETUR PATENTEDAPR 30 1914 3.; 807; 392

SHEET 16 0F 24 LRN START BRANCH TO LRN POINTER FOR CURRENT PATIENTLMORPH COUNTDOWN COUNTDOWNI MCREMENT LcouN-rafl LcougTER YES RETURN 0-LCOUNTER o- LTYPE;

LMORPH LR N POINTER LMORPHZ I I RETURN v No LSET 1 IN BIT POSITION OFLTYPE CORRESPONDING TO THE 1 IN MORPH ILNCREMENT LCOUNTER] Lcoug'rsa YES0 LRN POINTER;

I O- Ml 7 RETURN PATENIEnAPRQmQM' $807392 SHEET 17 [1F 24 MRP STARTUNLRND PUNLRND DOES LTYPE HAVE A 1 IN BIT POSITION IN WHICH MORPH HAS A1 O UNLRND 1+UNLRND (MPV START v H619 0- MULTPLE YES 1+ MULTIPLE RETHRNmimfimmwm 3307392 sum 18 0F 24 VRP START v YES LINCRENIENT VPB COUNTERFOR CURRENT PATIENT} N VPB COUNTER 25 YES 1*- FR EQUENT v RETURNemmgmmsomm I 3l807l3-9-2 SHEET, 19 HF 24 M FP START V 0-- MULTIFORM SETVMORPH FOR CURRENT PATIENT DOES VMORPH HAVE A! IN BIT POSITION IN WHICHLAST HAS A 1 YES N0 l- MULTIFORM SET A 1 IN BIT POSITION 0F VMORPHCORRESPONDING TO THE 1 IN LAST1 MORPH-v LAST RETURN

1. A method to be practiced on a machine for processing digital samplesof successive electro-cardiographic waveforms of a patient comprisingthe steps of: a. generating at least two different series of digitalfunction values from the successive digital samples being processed, b.performing tests on successive function values in each of said at leasttwo series, c. selecting the tests which are performed on said functionvalues in step (b) from a predetermined group of tests to obtainsElected tests that are dependent upon the results of the testsperformed on earlier function values, d. registering the sequences ofthe results of the tests performed in step (b) on the function valuesgenerated for the electro-cardiographic waveforms which occur during alearning interval, e. thereafter determining if the sequence of theresults of the tests performed in step (b) on the function valuesgenerated for a subsequent electro-cardiographic waveform is differentfrom all of the sequences registered during said learning interval, andf. characterizing the morphology of an electro-cardiographic waveform ofthe patient in accordance with the results of the tests performed instep (b).
 2. A method in accordance with claim 1 wherein the testsperformed in step (b) are comparisons of said function values withthreshold levels associated with respective ones of said series offunction values.
 3. A method in accordance with claim 2 furtherincluding the step of: d. continuously up-dating the threshold levelsused in the comparison tests in accordance with predetermined numbers ofmost recent respective function values.
 4. A method in accordance withclaim 3 further including the steps of: g. performing a special test onsuccessive function values in one series of function values to determinethe presence of an R wave in an electro-cardiographic waveform, and h.operating upon only particular function values in the performance ofsteps (e) and (f) for each electro-cardiographic waveform, theparticular function values being those generated from a group ofsuccessive digital samples which occur during a predetermined timeinterval which brackets and has a fixed time relationship to the timewhen the presence of the respective R wave is determined.
 5. A method inaccordance with claim 3 wherein the function values in one series offunction values generated in step (a) are proportional to the magnitudesof the digital samples being processed, and the function values in asecond series of function values generated in step (a) are proportionalto differences between the magnitudes of the digital samples.
 6. Amethod in accordance with claim 3 wherein the function values in oneseries of function values generated in step (a) are dependent upondifferences between the magnitudes of respective digital samples and theaverage magnitude of a predetermined number of earlier digital samples.7. A method in accordance with claim 3 further including the steps of:e. computing the sum of a group of function values in one series offunction values which are generated for each individualelectro-cardiographic cycle, f. computing the average of the sumscomputed for a predetermined number of most recent electro-cardiographiccycles, and g. determining if the sum computed in step (e) for anindividual electro-cardiographic cycle is greater than the averagecomputed in step (f) by more than a predetermined amount.
 8. A method inaccordance with claim 3 further including the steps of: e. performing aspecial test on successive function values in one series of functionvalues to determine the presence of an R wave in anelectro-cardiographic waveform, f. computing the time interval betweenthe determinations of the presence of two successive R waves, g.computing the average of the time intervals computed in step (f) for apredetermined number of most recent R waves, and h. determining if thetime interval computed in step (f) is greater than the average computedin step (g) by more than a predetermined amount.
 9. A method inaccordance with claim 3 further including the steps of: e. performing aspecial test on successive function values in one series of functionvalues to determine the presence of an R wave in anelectro-cardiographic waveform, f. computing the time interval betweenthe determinations of the presence of two successive R waves, g.computing the average of the Time intervals computed in step (f) for apredetermined number of most recent R waves, and h. determining if thetime interval computed in step (f) is less than the average computed instep (g) by more than a predetermined amount.
 10. A method in accordancewith claim 3 further including the steps of: e. performing a specialtest on successive function values in one series of function values todetermine the presence of an R wave in an electro-cardiographicwaveform, f. computing the time interval between the determinations ofthe presence of two successive R waves, g. computing the average of thetime intervals computed in step (f) for a predetermined number of mostrecent R waves, and h. determining if any time interval computed in step(f) is less than the average computed in step (g) by more than apredetermined amount and the immediately succeeding time intervalcomputed in step (f) is greater than the average computed in step (g) bymore than a predetermined amount.
 11. A method in accordance with claim3 further including the steps of: e. performing a special test onsuccessive function values in one series of function values to determinethe presence of an R wave in an electro-cardiographic waveform, f.computing the time interval between the determinations of the presenceof two successive R waves, and g. determining the presence of apremature ventricular beat in accordance with two time intervalscomputed in step (f) which separate three successive R waves and inaccordance with the characterizing in step (c) of theelectro-cardiographic waveform associated with the second of the threesuccessive R waves.
 12. A method in accordance with claim 11 furtherincluding the step of: h. counting the number of premature ventricularbeats whose presence are determined during a fixed time interval.
 13. Amethod in accordance with claim 3 further including the steps of: e.computing the sum of a group of function values in one series offunction values which are generated for each individualelectro-cardiographic cycle, f. computing the average of the sumscomputed for a predetermined number of most recent electro-cardiographiccycles, g. determining if the sum computed in step (e) for an individualelectro-cardiographic cycle is greater than the average computed in step(f) by more than a predetermined amount, h. performing a special test onsuccessive function values in one series of function values to determinethe presence of an R wave in an electro-cardiographic waveform, i.computing the time interval between the determinations of the presenceof two successive R waves, and j. determining the presence of apremature ventricular beat in accordance with two time intervalscomputed in step (i) which separate three successive R waves and inaccordance with a determination made in step (g) that the sum computedfor the electro-cardiographic cycle associated with the second or thethird of the three successive R waves is greater than the average by apredetermined amount.
 14. A method in accordance with claim 3 whereineach function value in one series of function values generated in step(a) is proportional to the sum of the magnitudes of a predeterminednumber of most recent digital samples.
 15. A method in accordance withclaim 1 wherein the tests performed in step (b) are comparisons of saidfunction values with threshold levels associated with respective ones ofsaid series of function values.
 16. A method in accordance with claim 15further including the step of: d. continuously up-dating the thresholdlevels used in the comparison tests in accordance with predeterminednumbers of most recent respective function values.
 17. A method inaccordance with claim 16 further including the steps of: e. registeringthe sequences of the results of the tests performed in step (b) on thefunction values generated for the electro-cardiographic waveformS whichoccur during a learning interval, and f. thereafter determining if thesequence of the results of the tests performed in step (b) on thefunction values generated for a subsequent electro-cardiographicwaveform is different from all of the sequences registered during saidlearning interval.
 18. A method in accordance with claim 16 wherein thefunction values in one series of function values generated in step (a)are proportional to the magnitudes of the digital samples beingprocessed, and the function values in a second series of function valuesgenerated in step (a) are proportional to differences between themagnitudes of the digital samples.
 19. A method in accordance with claim16 wherein the function values in one series of function valuesgenerated in step (a) are dependent upon differences between themagnitudes of respective digital samples and the average magnitude of apredetermined number of earlier digital samples.
 20. A method inaccordance with claim 16 further including the steps of: e. computingthe sum of a group of function values in one series of function valueswhich are generated for each individual electro-cardiographic cycle, f.computing the average of the sums computed for a predetermined number ofmost recent electro-cardiographic cycles, and g. determining if the sumcomputed in step (e) for an individual electro-cardiographic cycle isgreater than the average computed in step (f) by more than apredetermined amount.
 21. A method in accordance with claim 16 furtherincluding the steps of: e. performing a special test on successivefunction values in one series of function values to determine thepresence of an R wave in an electro-cardiographic waveform, f. computingthe time interval between the determinations of the presence of twosuccessive R waves, g. computing the average of the time intervalscomputed in step (f) for a predetermined number of most recent R waves,and h. determining if the time interval computed in step (f) is greaterthan the average computed in step (g) by more than a predeterminedamount.
 22. A method in accordance with claim 16 further including thesteps of: e. performing a special test on successive function values inone series of function values to determine the presence of an R wave inan electro-cardiographic waveform, f. computing the time intervalbetween the determinations of the presence of two successive R waves, g.computing the average of the time intervals computed in step (f) for apredetermined number of most recent R waves, and h. determining if thetime interval computed in step (f) is less than the average computed instep (g) by more than a predetermined amount.
 23. A method in accordancewith claim 16 further including the steps of: e. performing a specialtest on successive function values in one series of function values todetermine the presence of an R wave in an electro-cardiographicwaveform, f. computing the time interval between the determinations ofthe presence of two successive R waves, g. computing the average of thetime intervals computed in step (f) for a predetermined number of mostrecent R waves, and h. determining if any time interval computed in step(f) is less than the average computed in step (g) by more than apredetermined amount and the immediately succeeding time intervalcomputed in step (f) is greater than the average computed in step (g) bymore than a predetermined amount.
 24. A method in accordance with claim16 wherein each function value in one series of function valuesgenerated in step (a) is proportional to the sum of the magnitudes of apredetermined number of most recent digital samples.
 25. A method inaccordance with claim 1 further including the steps of: d. registeringthe sequences of the results of the tests performed in step (b) on thefunction values generated for the electro-cardiographic waveforms whichoccur during a learning interval, and e. thereafter determining if thesequence of the results of the test performed in step (b) on thefunction values generated for a subsequent electro-cardiographicwaveform is different from all of the sequences registered during saidlearning interval.
 26. A method in accordance with claim 1 furtherincluding the steps of: d. performing a special test on successivefunction values in one series of function values to determine thepresence of an R wave in an electro-cardiographic waveform, and e.utilizing only particular test results in the performance of step (c) tocharacterize each electro-cardiographic waveform, the particular testresults being those of tests performed in step (b) on a group ofsuccessive function values which are generated for a predetermined timeinterval which brackets and has a fixed time relationship to the timewhen the presence of the respective R wave is determined.
 27. A methodin accordance with claim 1 wherein the function values in one series offunction values generated in step (a) are proportional to the magnitudesof the digital samples being processed, and the function values in asecond series of function values generated in step (a) are proportionalto differences between the magnitudes of the digital samples.
 28. Amethod in accordance with claim 1 wherein the function values in oneseries of function values generated in step (a) are dependent upondifference between the magnitudes of respective digital samples and theaverage magnitude of a predetermined number of earlier digital samples.29. A method in accordance with claim 1 further including the steps of:d. computing the sum of a group of function values in one series offunction values which are generated for each individualelectro-cardiographic cycle, e. computing the average of the sumscomputed for a predetermined number of most recent electro-cardiographiccycles, and f. determining if the sum computed in step (d) for anindividual electro-cardiographic cycle is greater than the averagecomputed in step (e) by more than a predetermined amount.
 30. A methodin accordance with claim 1 further including the steps of: d. performinga special test on successive function values in one series of functionvalues to determine the presence of an R wave in anelectro-cardiographic waveform, e. computing the time interval betweenthe determinations of the presence of two successive R waves, f.computing the average of the time intervals computed in step (e) for apredetermined number of most recent R waves, and g. determining if thetime interval computed in step (e) is greater than the average computedin step (f) by more than a predetermined amount.
 31. A method inaccordance with claim 1 further including the steps of: d. performing aspecial test on successive function values in one series of functionvalues to determine the presence of an R wave in anelectro-cardiographic waveform, e. computing the time interval betweenthe determinations of the presence of two successive R waves, f.computing the average of the time intervals computed in step (e) for apredetermined number of most recent R waves, and g. determining if thetime interval computed in step (e) is less than the average computed instep (f) by more than a predetermined amount.
 32. A method in accordancewith claim 1 further including the steps of: d. performing a specialtest on successive function values in one series of function values todetermine the presence of an R wave in an electro-cardiographicwaveform, e. computing the time interval between the determinations ofthe presence of two successive R waves, f. computing the average of thetime intervals computed in step (e) for a predetermined number of mostrecent R waves, and g. determining if any time interval computed in step(e) is less than the average computed in step (f) by more than apredetermined amount anD the immediately succeeding time intervalcomputed in step (e) is greater than the average computed in step (f) bymore than a predetermined amount.
 33. A method in accordance with claim1 further including the steps of: d. performing a special test onsuccessive function values in one series of function values to determinethe presence of an R wave in an electro-cardiographic waveform, e.computing the time interval between the determinations of the presenceof two successive R waves, and f. determining the presence of apremature ventricular beat in accordance with two time intervalscomputed in step (e) which separate three successive R waves and inaccordance with the characterizing in step (c) of theelectrocardiographic waveform associated with the second of the threesuccessive R waves.
 34. A method in accordance with claim 33 furtherincluding the step of: g. counting the number of premature ventricularbeats whose presence are determined during a fixed time interval.
 35. Amethod in accordance with claim 1 wherein each function value in oneseries of function values generated in step (a) is proportional to thesum of the magnitudes of a predetermined number of most recent digitalsamples.
 36. A method to be practiced on a machine for processingdigital samples of successive electro-cardiographic waveforms of each ofa plurality of patients comprising the steps of: a. extending to saidmachine successive groups of digital samples, each group containing adigital sample of each of said patients, b. generating at least twodifferent series of digital function values for each patient from thesuccessive digital samples being processed for that patient, c.performing tests on successive function values in each of the at leasttwo series for each patient, d. selecting the tests which are performedon said function values in step (c) from a predetermined group of teststo obtain selected tests that are dependent upon the results of thetests performed on earlier function values, e. registering the sequencesof the results of the tests performed in step (c) on the function valuesgenerated for the electro-cardiographic waveform of each patient whichoccur during a learning interval, f. thereafter determining if thesequence of the results of the tests performed in step (c) on thefunction values generated for a subsequent electro-cardiographicwaveform of each patient is different from all of the sequencesregistered for that patient during said learning interval, and g.characterizing the morphology of an electro-cardiographic waveform ofeach patient in accordance with the results of the tests performed instep (c) on that patient''s function values.
 37. A method in accordancewith claim 36 wherein the tests performed in step (c) for each patientare comparisons of the function values of that patient with respectivethreshold levels associated with respective ones of the series offunction values of that patient.
 38. A method in accordance with claim37 further including the step of: e. continuously up-dating thethreshold levels for each patient used in the comparison tests inaccordance with predetermined numbers of most recent respective functionvalues of that patient.
 39. A method in accordance with claim 38 whereineach function value in one series of function values generated in step(a) for each patient is proportional to the sum of the magnitudes of apredetermined number of most recent digital samples of that patient. 40.A method in accordance with claim 36 wherein the tests performed in step(c) for each patient are comparisons of the function values of thatpatient with respective threshold levels associated with respective onesof the series of function values of that patient.
 41. A method inaccordance with claim 40 further including the step of: e. continuouslyup-dating the threshold levels for each patient used in the comparisontests in accordance with predetermined numbers of most recent respectivefunction values of that patient.
 42. A method in accordance with claim41 further including the steps of: f. registering the sequences of theresults of the tests performed in step (c) on the function valuesgenerated for the electro-cardiographic waveforms of each pateint whichoccur during a learning interval, and g. thereafter determining if thesequence of the results of the tests performed in step (c) on thefunction values generated for a subsequent electro-cardiographicwaveform of each patient is different from all of the sequencesregistered for that patient during said learning interval.
 43. A methodin accordance with claim 41 wherein each function value in one series offunction values generated in step (a) for each patient is proportionalto the sum of the magnitudes of a predetermined number of most recentdigital samples of that patient.
 44. A method in accordance with claim36 further including the steps of: e. registering the sequence of theresults of the tests performed in step (c) on the function valuesgenerated for the electro-cardiographic waveforms of each patient whichoccur during a learning interval, and f. thereafter determining if thesequence of the results of the tests performed in step (c) on thefunction values generated for a subsequent electro-cardiographicwaveform of each patient is different from all of the sequencesregistered for that patient during said learning interval.
 45. A methodin accordance with claim 36 further including the steps of: e.performing a special test on successive function values in one series offunction values for each patient to determine the presence of an R wavein an electro-cardiographic waveform of that patient, and f. utilizingonly particular test results in the performance of step (d) tocharacterize each electro-cardiographic waveform of a patient, theparticular test results being those of tests performed in step (c) on agroup of successive function values of that patient which are generatedfor a predetermined time interval which brackets and has a fixed timerelationship to the time when the presence of the respective R wave isdetermined.
 46. A method in accordance with claim 36 wherein thefunction values in one series of function values generated in step (a)for each patient are proportional to the magnitudes of the digitalsamples of that patient being processed, and the function values in asecond series of function values generated in step (a) for each patientare proportional to differences between the magnitudes of the digitalsamples of that patient.
 47. A method in accordance with claim 36wherein the function values in one series of function values generatedin step (a) for each patient are dependent upon differences between themagnitudes of respective digital samples of that patient and the averagemagnitude of a predetermined number of earlier digital samples of thatpatient.
 48. A method in accordance with claim 36 further including thesteps of: e. computing the sum of a group of function values in oneseries of function values for each patient which are generated for eachindividual electro-cardiographic cycle, f. computing for each patientthe average of the sums computed for that patient for a predeterminednumber of most recent electro-cardiographic cycles, and g. determiningif the sum computed in step (e) for an individual electro-cardiographiccycle of each pateint is greater than the average computed in step (f)for that patient by more than a predetermined amount.
 49. A method inaccordance with claim 36 further including the steps of: e. performing aspecial test on successive function values in one series of functionvalues for each patient to determine the presence of an R wave in aelectro-cardiographic waveform of that patient, f. computing the timeinterval between the determinations of the presence of two successive Rwaves of each patient, g. computing for each patient the average of thetime intervals computed in step (f) for that patient for a predeterminednumber of most recent R waves, and h. determining if the time intervalcomputed in step (f) for each patient is greater than the averagecomputed in step (g) for that patient by more than a predeterminedamount.
 50. A method in accordance with claim 36 wherein each functionvalue in one series of function values generated in step (a) for eachpatient is proportional to the sum of the magnitudes of a predeterminednumber of most recent digital samples of that patient.
 51. A method forprocessing successive electrocardiographic waveforms of a patientcomprising the steps of: a. generating at least two different series ofsampled functions from the successive waveforms being processed, thesampled functions in each series being generated at a rate substantiallyhigher than the rate at which successive wave-forms occur, b. performingtests on successive sampled functions in each of said at least twoseries, c. selecting the tests which are performed on said sampledfunctions in step (b) from a predetermined group of tests to obtainselected tests that are dependent upon the results of the testsperformed on earlier sampled functions, d. registering the sequences ofthe results of the tests performed in step (b) on the sampled functionsgenerated for the electro-cardiographic waveforms which occur during alearning interval, e. thereafter determining if the sequence of theresults of the tests performed in step (b) on the sampled functionsgenerated for a subsequent electro-cardiographic waveform is differentfrom all of the sequences registered during said learning interval, andf. characterizing the morphology of an electro-cardiographic waveform ofthe patient in accordance with the results of the tests performed instep (b).
 52. A method in accordance with claim 51 wherein the testsperformed in step (b) are comparisons of said sampled functions withthreshold levels associated with respective ones of said series ofsampled functions.
 53. A method in accordance with claim 52 furtherincluding the step of: d. continuously up-dating the threshold levelsused in the comparison tests in accordance with predetermined numbers ofmost recent respective sampled functions.
 54. A method in accordancewith claim 53 wherein each sampled function in one series of sampledfunctions generated in step (a) is proportional to the sum of themagnitudes of a predetermined number of most recent samples of anelectro-cardiographic waveform.
 55. A method in accordance with claim 51wherein the tests performed in step (b) are comparisons of said sampledfunctions with threshold levels associated with respective ones of saidseries of sampled functions.
 56. A method in accordance with claim 55further including the step of: d. continuously up-dating the thresholdlevels used in the comparison tests in accordance with predeterminednumbers of most recent respective sampled functions.
 57. A method inaccordance with claim 56 further including the steps of: e. registeringthe sequences of the results of the tests performed in step (b) on thesampled functions generated for the electro-cardiographic waveformswhich occur during a learning interval, and f. thereafter determining ifthe sequence of the results of the tests performed in step (b) on thesampled functions generated for a subsequent electro-cardiographicwaveform is different from all of the sequences registered during saidlearning interval.
 58. A method in accordance with claim 56 wherein eachsampled function in one series of sampled functions generated in step(a) is proportional to the sum of the magnitudes of a predeterminednumber of most recent samples of an electro-cardiographic waveform. 59.A method in accordance with claim 51 further including the steps of: d.registering the sequences of the results of the tests pErformed in step(b) on the sampled functions generated for the electro-cardiographicwaveforms which occur during a learning intervals, and e. thereafterdetermining if the sequence of the results of the tests performed instep (b) on the sampled functions generated for a subsequentelectro-cardiographic waveform is different from all of the sequencesregistered during said learning interval.
 60. A method in accordancewith claim 51 further including the steps of: d. performing a specialtest on successive sampled functions in one series of sampled functionsto determine the presence of an R wave in an electro-cardiographicwaveform, and e. utilizing only particular test results in theperformance of step (c) to characterize each electro-cardiographicwaveform, the particularl test results being those of tests performed instep (b) on a group of successive sampled functions which are generatedfor a predetermined time interval which brackets and has a fixed timerelationship to the time when the presence of the respective R wave isdetermined.
 61. A method in accordance with claim 51 wherein the sampledfunctions in one series of sampled functions generated in step (a) areproportional to the magnitudes of samples of the waveforms beingprocessed, and the sampled functions in a second series of sampledfunctions generated in step (a) are proportional to differences betweenthe magnitudes of samples of the waveforms.
 62. A method in accordancewith claim 51 wherein the sampled functions in one series of sampledfunctions generated in step (a) are dependent upon differences betweenthe magnitudes of respective samples of the waveform being processed andthe average magnitude of a predetermined number of earlier samples ofthe waveform.
 63. A method in accordance with claim 51 further includingthe steps of: d. computing the sum of a group of sampled functions inone series of sampled functions which are generated for each individualelectro-cardiographic cycle, e. computing the average of the sumscomputed for a predetermined number of most recent electro-cardiographiccycles, and f. determining if the sum computed in step (d) for anindividual electro-cardiographic cycle is greater than the averagecomputed in step (e) by more than a predetermined amount.
 64. A methodin accordance with claim 51 further including the steps of: d.performing a special test on successive sampled functions in one seriesof sampled functions to determine the presence of an R wave in anelectro-cardiographic waveform, e. computing the time interval betweenthe determinations of the presence of two successive R waves, f.computing the average of the time intervals computed in step (e) for apredetermined number of most recent R waves, and g. determining if thetime interval computed in step (e) is greater than the average computedin step (f) by more than a predetermined amount.
 65. A method inaccordance with claim 51 wherein each sampled function in one series ofsampled functions generated in step (a) is proportional to the sum ofthe magntiudes of a predetermined number of most recent samples of anelectro-cardiographic waveform.